Environmental Factor, November 2011, National Institute of Environmental Health Sciences

EMS honors NIEHS-funded researcher

By Ian ThomasNovember 2011

Holland, left, and Huen are shown at the UC Berkeley graduation ceremony in 2009.
(Photo courtesy of Karen Huen)

Center For The Health Assessment Of Mothers And Children Of Salinas. Center of Excellence in Children's Environmental Health. University of California, Berkeley.

The Environmental Mutagen Society (EMS) has selected “Effects of PON polymorphisms and haplotypes on molecular phenotype in Mexican-American mothers and children,” a study from Karen Huen, Ph.D., as its top publication of 2011 from a student or new investigator. Backed by joint funding from NIEHS and the U.S. Environmental Protection Agency (EPA), the study(http://www.ncbi.nlm.nih.gov/pubmed/20839225) explores the genetic differences between Mexican-American and Caucasian mothers and children with regard to the effects of paraoxonase (PON), a protective metabolic enzyme that can detoxify some organophosphate pesticides (OPs).

Nina Holland, Ph.D.(http://coeh.berkeley.edu/people/faculty/holland.htm), the study's lead researcher, credited her fellow scientists from UC Berkeley for much of the project's success. Study participants were drawn from the Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS), a longitudinal birth cohort study funded by a grant(http://projectreporter.nih.gov/project_info_description.cfm?aid=8304372&icde=10017954) from NIEHS.

By resequencing PON genes in 30 children and mothers from the Salinas Valley in California, followed by high-throughput genotyping and haplotype analyses for more than 400 mother-child pairs, Huen and her team identified a total of 90 genetic variants, many of which were novel, functionally significant, and noticeably varied from their Caucasian counterparts.

“Initially, we expected to see the effects of some PON genetic polymorphisms on the quantity and efficiency of organophosphate detoxification,” explained Holland. “In the end, we found that, in the case of exposure, children in some populations remain more vulnerable than adults until nearly 9 years of age, [and] some of them may be more than 50 times more susceptible than others due to their genetic makeup.”

The whole picture

While the results of this study clearly indicate that PON status can influence levels of susceptibility among various population and age groups, Huen and Holland are quick to point out that several additional factors should be examined when evaluating new ways to protect the public from pollutants like OPs.

“Many emerging public health problems, such as childhood obesity and neurodevelopment issues, may be the result of prenatal or adolescent exposures to environmental pollutants,” Holland explained. “At the same time, it's also essential for future research to factor additional parameters, such as diet and lifestyle, when determining the overall impact on the health of a given population.”

A collective effort

Still, researchers insist that joint partnerships between like-minded organizations will ultimately be the key to beneficial research moving forward.

“This is the age of genomics and personalized medicine,” Holland observed. “Partnerships, like the one between NIEHS and EPA which funded this study, will be crucial in producing the kind of research that can actually shape policy and protect children and pregnant women from the harmful effects of substances such as OPs.”

Since its founding in 1969, EMS has been dedicated to the promotion of critical research into the causes and consequences of damage to the genome and epigenome, for the purpose of ensuring a healthy, sustainable environment for future generations. Visit the EMS website(http://www.ems-us.org/) to learn more.

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